[bdbxml] DATE_TIME format

what is the format for a DATE_TIME XmlValue.  The Getting Started guide
shows:
 
"2005-10-5T04:18:36"
 
which appears to be:

yyyy-MM-dTHH:mm:ss
 
Can't figure out a few things:
 
is only 1 date (date of the month) field ok, or is 2 acceptable (9 vs
09)?  Usually, 2 is required.
 
What is the letter T for between the date and Time?
 
Is the hour done on a 24 hour basis?  If so, is this 0 to 23 or 1 to 24?
 
 
I tried just a date.toString() method, but that did not work.  Somewhere
on the web it shows that as being ok.